The Flaming Arrow of Amazing Ability is a technique used by Nagato through the Asura Path.
Using the body modification ability of the Asura Path, the user compresses a high amount of chakra at the slit of its wrist before releasing it, causing its detachable hand to be fired with tremendous force. It has enough destructive power to easily break through thick bedrock. As the hand portion is protected with chakra, it allows it to remain unscathed. When the attack is complete, the hand is drawn back like a magnet by chakra in the wrist, reattaching itself.
The kaiwan (怪腕) in Kaiwan no Hiya can be translated in two ways. The first and most common way is the idiomatic way: "an amazing or remarkable ability". The second way is by translating the kanji directly: "mysterious or suspicious arm", making the name a pun.